Dentistry is the science concerned with the diagnosis, prevention, and treatment of diseases of the teeth, gums, and related structures of the mouth and includes the repair or replacement of defective teeth. Dental (i.e., relating to, or for the teeth) treatments involve those compositions, articles and processes encompassed within the field of dentistry. The terms "non-dental applications and treatments" and "non-dental-related", as used herein and in the claims hereof, address activities exclusive of activities that are part of the field of dentistry.
Geristore.TM. and Tenure.TM., sold by Den-Mat Corporation, Santa Maria, Calif., are promoted for certain uses in dentistry. U.S. Pat. Nos. 4,738,722, 5,334,625 and 5,151,453, incorporated herein by reference, describe Geristore.TM.. Geristore.TM. is a small particle composite that contains fluoride, is radiopaque and hydrophilic. It has low-cure shrinkage, low coefficient of thermal expansion and high strength. It aggressively bonds by chemical coupling to dentin, enamel, composites used in dentistry, porcelain and metal, such as stainless steel. It is a paste/paste formulation that is easy to mix. It is capable of rapid cure by exposure to room temperature and for more rapid cure, by exposure to light. In addition, though it contains a fluoride, which could be toxic when ingested in large dosages, it is biocompatible and safe to use within a human or other animal when applied topically.
Tenure.TM. is a solvent based crosslinkable acrylic resin, provided as a solution/solution formulation. Its composition is described in U.S. Pat. No. 4,964,911, patented Oct. 27, 1990, and more effectively disclosed in allowed copending application Ser. No. 965,102, filed Oct. 22, 1992, to issue as U.S. Pat. Re 34,937, the disclosure of which is incorporated by reference. It is not an ionomer and does not release fluoride ion. It is less hydrophilic than Geristore.TM.. It too is a crosslinkable resin. It contains a volatile solvent (typically acetone), which readily evaporates. After evaporation, a film of the resin rapidly cures in situ. Tenure.TM. bonds by chemical coupling to dentin, enamel, porcelain, metal and the composites typically used in dentistry. It has been recommended for use with Geristore.TM. in chemically bonding Geristore.TM. to dentin or enamel.
Galan, Journal Of Esthetic Dentistrv, Vol. 3, No. 6, (Nov./Dec. 1991), describes the general use of Geristore.TM. in the restoration of teeth and lesions both supra and subgingivally located.
M. Dragoo (unpublished) has used Geristore.TM. in subgingival restorations of teeth to treat subgingival root resorption, split roots, endo perforation, tooth fracture, external root resorption and root coverage over previously restored and/or eroded root surfaces. He found the Geristore.TM. aided in rebuilding biologic width, resulting in new tissue attachment, and minimized plaque induced gingivitis.
There is much art on the use of hydroxyethylmethacrylate ("HEMA") to make hygroscopic polymers such as a homopolymer of HEMA ("PHEMA"). Such HEMA based polymers typically form water swellable hydrogels. HEMA contains the sym. (or 1,2-) ethylene bis-methacrylate (ethylene glycol dimethacrylate) as a byproduct. This byproduct crosslinks the HEMA based polymers to allow formation of useful hydrogels. One such hydrogel form is used to make soft contact lens by cast molding HEMA containing small amounts of ethylene bis-methacrylate. One advantage of PHEMA based systems that allows use in physiological applications is the biocompatibility of the polymer. However, their use as described in the patent literature has been limited merely to transporting drugs and other materials to a bodily function based on their absorptive qualities or as an inert interface about a device to render that device biocompatible. See for example, U.S. Pat. No. 3,566,874, which describes the encapsulation of a catheter with a casting syrup of HEMA. The hydrogel form of the polymer of HEMA ("PHEMA") is renowned for its capacity to absorb moisture to generate a swollen film. Some patents describe PHEMA products into which other ingredients have been absorbed. In this respect, the PHEMA product, as such, is merely a reservoir for that ingredient. U.S. Pat. No. 3,566,874 describes the inclusion in a HEMA casting syrup of a germicide or an antibiotic. U.S. Pat. No. 4,303,066, makes a burn dressing by dispensing separate phases of a PHEMA and a high boiling liquid on a burn to serve as a dressing. As a consequence, the absorptive characteristic of PHEMA is being used only for the high boiling liquid which is provided supposedly for heat transfer purposes. U.S. Pat. No. 3,674,901 describes the coating of a HEMA based solvent solution to coat surgical suture threads. The patent includes antibiotics, antiseptics or bactericides absorbed into the cured resin. In this case, however, the resin is foamed first before the adsorption takes place. In U.S. Pat. No. 3,849,185, a HEMA coumarone-indene type resin casting material is mixed with materials such as heparin and used as a coating material. On the other hand, U.S. Pat. No. 3,868,447 describes a highly filled solvent-based HEMA paste to which biologically active ingredients can be added. The paste has been described for use in dental applications, such as a cover for dental fillings, or as a carrier for Novocain.TM. in dental surgery.
Though HEMA and PHEMA contain hydroxyl groups and hydroxyl groups are thought to aid in adhesion, the adhesion of such groups to a physiologically active surface is materially and adversely affected by the presence of water at the surface. Consequently, bonding of HEMA to a physiologically involved surface which contains moisture at its surface requires some ingredient in the resin that aids in bonding to such a surface.